Multi-component mixing apparatus

ABSTRACT

An apparatus for mixing a plurality of separate flowable materials in desired proportions. The apparatus includes a positive displacement piston pump for each material and a mixer. The piston displacement of each pump is regulated, either by an oil reservoir system or by adjustable crank arms, so that each pump delivers material in the proper proportion. The outlet of each pump is connected to the mixer, wherein the materials are thoroughly mixed by a rotating agitator vane and delivered as a thoroughly mixed composite of all of the individual materials.

Roeser [451 Aug. 15, 1972 MULTI-COMPONENT MIXING APPTUS [72] Inventor:John O. Roaer, Arlington Heights,

[73] Assignee: Otto Engineering, Inc., Carpentersville, 111.

[22] Filed: June 24, 1970 [21] Appl. No.: 48,981

3,220,801 1 1/1965 Rill ..259/8 3,297,306 1/1967 Napier ..25 9/83,482,822 12/1969 Krizak ..259/8 Primary ExaminerRobert W'. JenkinsAttorney-Robert D. Silver 1 5 ABSTRACT An apparatus for mixing aplurality of separate flowable materials in desired proportions. Theapparatus includes a positive displacement piston pump for each materialand a mixer. The piston displacement of each pump is regulated, eitherby an oil reservoir system or by adjustable crank arms, so that eachpump delivers material in the proper proportion. The outlet of each pumpis connected to the mixer, wherein the materials are thoroughly mixed bya rotating agitator vane and [56] References Cited delivered as athoroughly mixed composite of all of UNITED STATES PA the individualmaterials.

3,207,486 9/1965 Rosenthal ..259/8 11 Claims, 11 Drawing Figures sc E.106 Jag Q5 52 V J05 4 L j] PUMP i l] RESERVOIR PUMP C NH 51 J0 l' Viill' [J01 53 V in 1| 1 jaz OIL "A SOURCE 10/ "3" SOURCE RESERVOIR MO 1OR 11 M IX IN 6 1 c IIA M [SEA 1" PATENTEDAUS 15 m2 w 14' SOURCE3,684,250 SHEET 1 [1F 4 so J cE .106

Q5 2. V 99 Z J] OIL RESERVOIR We PUMP W /0 55 Ill! 1 1 r v h U A% sE1%o/R "a" SOUR c E M MIX/N6 CHAMBER J W I 3 MULTI-COMPONENT MIXINGAPPARATUS BACKGROUND This invention relates to a mixing apparatus, and,more particularly, to a mixing apparatus for mixing a plurality ofseparate flowable materials in desired proportions.

It is often desirable to deliver a mixture comprises of a plurality offlowable materials which must be mixed in definite proportions justprior to delivery, for example, multi-component flowable adhesives,sealers, foams such as epoxides, polyurethanes, polyesters, and thelike. In many cases, it is important not only that the multiplecomponents be mixed in relatively exact proportions but that the mixingoccur only shortly before the mixture is used. For example, theinvention is particularly suitable for delivering flowable epoxy resinsand flowable hardeners or catalysts in desired proportions. Since thehardener or catalyst reacts with the resin relatively quickly, it isdesirable that the mixing of the components occur just before themixture is to be uses or applied.

While mixing apparatus for multi-component mix tures have been availablein the past, these have generally been complicated and expensive systemswhich have been subject to a number of disadvantages. For example, it isimportant that the mixing system have a minimum of moving parts such asvalves and the like which can be affected by the flowable materials,which frequently are of relatively high viscosity. Further, the variousparts of the system should be able to be cleaned without difficulty. Theusual procedure for mixing materials such as epoxy resins has been topump the components from drums by air-driven material pumps to measuringcylinders and then to a mixer through hoses, four-way valves and othercircuitry. Each of the various parts of prior art mixing systems has itsparticular problems due to the high pressure involved and thedisagreeable nature of the materials being handled. Each part presentsone or more opportunities for the resins to leak from the system, and ablockage in any of the valves, piping or cylinders can cause eitherpartial or complete blocking in the flow of one or the other of theresins. Since the other resin would continue flowing, the operator ofthe mixing system might not be aware of the blockage, and the materialdelivered by the mixing system would not be properly proportioned.

The resins are delivered from the measuring cylinders to a mixer, andthe usual practice has been to provide a fairly large volume mixer withcomplicated agitators consisting of a series of propellers whichprogressively agitate and shear the material as it passes through themixer. The major drawbacks of this system have been the high cost of thelarge and relatively complicated mixers and also the fact that theycontain a good deal of mixed resin. Large bodies of mixed resin shouldbe avoided since the materials being handled are exothermic, and theheat generated tends to have an avalanche effect on the hardening of theresins. Large mixing chambers cannot be thus filled and static for anylength of time, or the heat will cause all of the resin therein to reactand become hardened.

SUMMARY The invention provides a simple apparatus with a minimum ofmoving parts. The material pumps are connected directly to the mixerwithout the use of valves or complicated piping, and the components ofthe system are easily disassembled for cleaning. The individual pumpsare synchronized by a simple proportioning system which insures thedelivery of each of the component materials in the proper proportions,and each pump delivers an accurate, controlled amount of material. Theinlet and outlet portions of the pump may provide full annular flow toreduce the pump stroke and to enable fast opening and closing of theinlet and outlet ports without compression lock. The mixer comprisesthree sections which are readily separated for cleaning, and the mixingchamber is of relatively small volume. The mixing agitator is rotativelydriven but may float within the mixing chamber, and the design of theagitator insures good mixing of the resin components.

DESCRIPTION OF THE DRAWING The invention will be explained inconjunction with illustrative embodiments shown in the accompanyingdrawings, in which FIG. 1 is a schematic view of a mixing systemembodying the invention;

FIG. 2 is a sectional elevational view of one of the measuring pumps;

FIG. 3 is an enlarged view of a portion of FIG. 2;

FIG. 4 is a sectional view taken along the line 4-4 of FIG. 2;

FIG. 5 is a sectional elevational view of the mixer;

FIG. 6 is a sectional view taken along the line 66 of FIG. 5;

FIG. 7 is a fragmentary side view taken along the line 7-7 of FIG. 5;

FIG. 8 is a sectional view taken along the line 8--8 of FIG. 5;

FIG. 9 is an exploded fragmentary view of a portion of the mixer;

FIG. 10 is an elevational view partly in section of another measuringpump showing an alternate proportioning means and sealing means;

FIG. 11 is an enlarged view of a portion of FIG. 10.

DETAILED DESCRIPTION OF THE SPECIFIC EMBODIMENT My mixing system isshown schematically in FIG. I, and the particular system illustrated isfor use in mixing two component materials such as resins A and B. It isto be understood, however, that my mixing system can be used for mixingmore than two component materials.

The system includes measuring pumps 10 and 11 for resins A and B,respectively, and a mixer 12 connected to the outlet of pumps 10 and 1 1by conduits l3 and 14, respectively. As will be explained more fullyhereinafter, each of the measuring pumps delivers a measured shot ofmaterial in the proper proportion to the mixer 12, where the componentsare mixed and delivered through the nozzle 15 of the mixer.

Referring now to FIG. 2, the measuring pump 10 includes an air cylinderportion 16, an intermediate portion 17, and a measuring portion 18. Theair cylinder portion 16 includes a cylinder 19 provided with a centralbore 20 and ports 21 and 22. The cylinder 19 is joined to theintermediate connecting portion 17 by block 23 which slidably supportspiston rod 24. Suitable packing (not shown) is carried by the block 23for sealingly engaging the piston rod to seal the lower end of the aircylinder. The upper end of the piston rod 24 is provided with a threadedend portion 25 of reduced diameter which carries piston assembly 26. Thepiston assembly includes a gasket 27 which sealingly engages the wall ofthe cylinder and which is held between a pair of washers 28 and 29. Thewasher 28 engages shoulder 30 provided by the narrowed end portion ofthe piston rod, and the piston assembly is secured by nut 31 threadedlyreceived by the threaded end portion.

The intermediate connecting portion 17 is provided with a central bore32 into which the lower end of piston rod 24 extends, and the wall ofthe intermediate portion may be provided with a pair of opposed openings33 adjacent the lower end thereof.

Measuring portion 18 is secured to the lower end of the intermediateportion 17 and is also provided with a central bore 34 which is axiallyaligned with the bores 32 and 20. Bore 34 provides a measuring chamberportion 35 and a radially enlarged outlet chamber portion 36. Inlet port37 communicates the measuring portion 35 of the bore with a suitablesource of the material to be pumped, and outlet port 38 communicates theoutlet portion of the bore with the mixer.

Plunger 39 is snugly received by the bore 34 and provides asubstantially fluid-tight seal for the resin which is to be pumped. Thepiston rod 24 is provided with a threaded lower end 40, and nut 41carried by the upper end of the plunger is threadedly secured thereto. Acentral bore 42 is provided in the plunger 39 for about half the lengththereof and the upper end of the bore 42 communicates with the outsideof the plunger through four cross drilled holes 43 located about 90apart.

The lower end of the intermediate portion 17 is provided with a cavity44 (FIG. 3) which receives a pair of O-rings 45a and 45b which sealinglysurround the plunger 39 and which are spaced apart a spacer sleeve 46.An abutment or shoulder 47 extends radially inwardly from the wall ofthe outlet bore chamber 36 and retains the O-rings within the cavity 44.The shoulder 47 may extend circumferentially about bore or it may besegmented and extend inwardly at circumferentially spaced, discretelocations.

The bore 34 is enlarged adjacent the inlet port 37 to provide anenlarged inlet chamber 48 which surrounds the plunger 39 (FIG. 4). Inthe particular embodiment illustrated, the enlarged inlet chamber isprovided by the intersection of the A inch bore for the inlet port 37and the /3 inch bore 34. Other ways of obtaining a circumferential, or asubstantially circumferential enlargement of the bore 34 adjacent theinlet port can readily be envisioned.

The plunger 39 is shown in FIG. 2 at the beginning of a downward stroke,and the lower end thereof is spaced slightly above the bottom wall 48aof the annular inlet chamber 39. The cross drilled holes 43 in theplunger are positioned relative to the O-ring 45b and the shoulder 47 sothat the cross drilled holes will not pass below the O-ring 45b into theradially enlarged outlet portion 36 of the bore 34 until the lower endof the plunger reaches the bottom wall 48a of the enlarged inlet chamber48.

Since the resin is being forced through the inlet port 37 into theenlarged inlet chamber 48, there is full 360 flow at the plunger end,and the pressure exerted by incoming resin is equalized all the wayaround the plunger. This substantially eliminates the possibility thatthe plunger will be forced to one side as the resin is forced which mayresult in compression lock or binding of the plunger.

A nut 49 is secured to the lower end of the measuring portion 18 of thepump, and adjusting rod 50 is snugly receive by the central bore 34 ofthe measuring portion 18 and provided with a threaded lower end 50a. Theaxial position of the adjusting rod 50 within the central bore 34 can bevaried by rotating the adjusting rod relative to the nut 49. The rod 50serves to limit the downward movement of the plunger 39, therebyregulating the amount of resin that is pumped. It is to be understood,however, that other means of stroke adjustment and limitation might beemployed.

In operation, the position of the plunger 39 shown in FIG. 2 can beconsidered the start of a downward or measuring stroke. Resin issupplied from resin source 51 (FIG. 1) through the material inlet port37 to the inlet chamber 48 and the measuring chamber 35 of the centralbore 34. Pressurized air from a suitable air source 52 (FIG. 1) issupplied to the cylinder 19 throughair inlet 21 to drive the piston rod24 and plunger 39 downwardly, and the pressure developed on the resincauses the resin to flow upwardly through the central bore 32 of theplunger and through the cross drilled holes 43. When the lower end ofthe plunger passes the bottom wall 48a of the inlet chamber, the crossdrilled holes will pass the O-ring 45b, and resin will flow into theradially enlarged outlet portion 36, through the outlet port 38 and tothe mixer 12 through conduit 13 (FIG. 1). The forward or downward strokeof the plunger produces considerable pressure which is limited only bythe amount of force supplied to the piston rod 24 by the air source.Commonly, this is in the range of 400 to 2,000 pounds per square inch.Since some resins which may be mixed are highly viscous, it is desirableto apply this much pressure in order to get adequate flow.

After the initial few strokes of the plunger, resin will fill the inletchamber 48, measuring chamber 35,

. plunger bore 42, and cavity 44 so that resin will not flow through theplunger until the cross drilled holes 43 pass the O-ring 45b. Until thishappens the downward stroke of the plunger will exert pressure on theresin and may cause backflow through the inlet port and into the inletconduit. If enough pressure is exerted, the inlet conduit may evenrupture. It is therefore desirable that the plunger stroke before thecross drilled holes are opened be relatively short, and I achieve thiswith my pump design.

My plunger need travel only a short distance between the point in whichthe inlet end of the plunger is fully opened and the outlet end fullyclosed and the point in which the outlet end of the plunger is fullyopened and inlet end is fully closed. Because there is full resin flowaround the circumference of the lower plunger end, this end need bepositioned only slightly above the bottom of the annular inlet chamberbefore beginning a downward stroke. Assoon as the plunger end reachesthe bottom wall of the inlet chamber, the inlet port is completely andsuddenly closed. At the outlet end, no resin will flow through the crossdrilled holes until the holes pass the O-ring 45b, but as soon as theholes pass the O-ring, the circurnferentially enlarged outlet bore 36permits full 360 flow and the outlet end of the plunger becomes fullyopened.

Conversely, when the plunger is retracted, the lower end of the plungerbecomes fully open to resin flow almost immediately upon passing abovethe bottom wall of the inlet chamber, and the outlet end becomes fullyclosed when the cross drilled holes reach the O-ring 45b. Thus, verylittle axial movement of the plunger is necessary to bring either end ofthe plunger from a fully open to a fully closed position or vice versa,and the total stroke of the plunger is relatively short.

In certain prior art pumps, the inward and outward flow of the resinwould be through ports which communicate with the axial bore of thepump. Before the inlet or outlet ports could be changed from a fullyopen to a fully closed condition, or vice versa, the plunger would haveto travel a distance corresponding to the axial dimension of the port.

For example, in one specific embodiment of my pump the diameter of theinlet port 37 was 7/16 in., and the outside diameter of the plunger 39was in. The cross sectional area of resin flow through the port wastherefore 1r (7/32) sq.in. or 0.151 sq. in. In order to get the sameflow past the end of the plunger into the measuring chamber, the plungershould be raised approximately a distance d above the bottom 48a of theinlet chamber, where d=0.l26 in.

If the inlet port opened directly into the axial bore of the pump, theplunger would have to travel approximately the same distance as the portdiameter, or 7/16 in. (0.437 in.) before full flow into the axial borewas achieved.

Conversely, my plunger need travel downwardly only about 0.126 in.before the inlet port is closed and the outlet port is open whereas acomparable prior art pump would have to travel about 0.437 in. Thisdifference in stroke can be significant because of the considerablepressure that can be applied bythe plunger. If the downward movement ofthe plunger before the inlet port is closed and the outlet port isopened is too long, the back pressure created in the inlet conduit couldrupture the conduit or cause a hydraulic lock of plunger movement, ordamage or strain upstream apparatus.

As will be explained more fully hereinafter, the plunger 39 is returnedby switching the air pressure from inlet 21 to inlet 22 of the cylinderto force the piston rod 24 upwardly. On the return stroke of theplunger, reduced pressure or vacuum is created in the pose a portion ofthe inlet chamber 48, or the resin can be drawn back through the centralbore 42 of the plunger from the conduit 13 and mixer 12 where it wasinitially delivered. Little if any resin will be returned to themeasuring chamber because the viscosity of the resin limits its abilityto flow under the small amount of pressure that is available in theevacuated measuring chamber, which theoretically can never be more than15 psi. If relatively thin materials are being pumped, it may bedesirable to position a check valve in the exit line from the pump.However, the slight backflow of material from the material outlet duringthe return stroke of the plunger is actually desirable since it causes aslight sucking back at the nozzle 15 of the mixer which preventsdribbling or stringing of the resin from the nozzle. Also, the returnstroke of the plunger is generally considerably faster than the forwardstroke. The only thing restricting the return stroke is the small vacuumat the forward end of the plunger, whereas on the forward stroke thereis as much pressure as needed to develop flowing of the resin material.Accordingly, during the return stroke of the plunger, there isessentially a complete vacuum in the chamber that is maintained untilthe forward end of the plunger passes the bottom wall of the inletchamber 48, at which time resin flows into the measuring chamber,impelled both by the residual vacuum and by any pressure that may beapplied to the resin source or reservoir.

As the lower end of the plunger moves upwardly past the bottom wall 480of the inlet chamber, the cross holes 43 in the plunger are sealed bythe O-ring gland 45b so that material flow through the pump iseffectively blocked in both directions. This is desirable to prevent anycontinued suction of material back from the outlet port 38 and toprevent material from being pushed through the pump by pressure appliedto the material at the material reservoir. Any flow from the reservoirthrough the pump could cause inaccurate measurement of one of thecomponents and result in improper mixing and proportioning of themixture.

It will be appreciated that the flow passages of the pump are opened andclosed by the considerable force applied to the piston rod 24, and theflow passages are closed by shearing action. It is therefore highlyunlikely that the flow passages should fail to open or close. Further,it is apparent that the timing of the opening and closing of the flowpassages is synchronized with the plunger movement, and no auxiliarymechanism is necessary to accomplish this cooperation. Accordingly, theneed for high-pressure four-way material valves and other complicatedsynchronizing or proportioning apparatus is eliminated.

Measuring pump 10 is independent of the type of material reservoir orpumping that is used. For example, if the resin is not too thick, itmight be allowed to flow into the measuring chamber by gravity alone. Ihave found that gravity feed works well even on materials that have aviscosity of about 2,000 centipoise. The material could also be suppliedto the measuring chamber by simple pressure pots or by air driverhighpressure barrel pumps, both of which are well known in the art. Themeasuring pump works equally well whether the material is fed by gravityor by a pressure of several hundred psi, and it is unnecessary to makeany adjustment in the measuring pumps which might be required if checkvalves or relief valves were used.

The measuring pump 1 1 is identical to the measuring pump 10, anddelivers material B from material source 53 through conduit 14 to themixer 12.

Referring now to FIG. 5, the mixer 12 includes a driving portion 55 anda mixer housing 56 which includes a distribution portion 56a and amixing portion 56b. The driving portion 55 includes a suitable motor 58and a rotating driving shaft 59, and the motor can be a conventionalair-driven motor for rotating the driving shaft 59 at about 1,000 rpm.The motor 58 is secured by bolts 60 to a mounting block 61 whichconnects the motor to the mixer housing, and the lower end of themounting head 61 includes an outwardly extending flange 62 which isconnected to a generally cylindrical distribution head 63 by bolts 64.The distribution head 63 is provided with a central bore 65 and a pairof radially inwardly extending inlet ports 66 and 67. The inner end ofinlet port 66 communicates with the bore 65 by means of passage 68 whichis angled axially upwardly, while the inlet port 67 communicates withthe bore 65 by means of passage 69 which is angled axially downwardly,thereby providing axially spaced inlet openings.

The mixing section 56b of the mixer includes an elongated generallycylindrical mixing tube 70 having an internal mixing chamber 71 thereinand a nozzle or ejector opening 15 in the lower end thereof. The upperend of the mixing tube 70 includes radially enlarged shoulders 73 whichengage correspondingly shaped recesses 74 provided in an annularclamping ring 75, and the mixing tube is secured to the distributionhead 63 by bolts 76 which connect the clamping ring to the distributionhead. The radially enlarged upper end portion of the mixing tubeprovides an annular cavity 77 which receives O-ring 78. The O-ring iscompressed between the mixing tube and the distribution head to providea seal therebetween.

A generally helical agitator or mixing vane 80 is rotatably received bythe mixing chamber 71 and is rotated by shaft 81 which is operativelyconnected to the drive shaft 59 of the motor. Referring to FIGS. and 8,the lower end of the drive shaft is counterbored as at 82 for receivingshaft 81, and the upper end of the shaft 81 is provided with a slot 81a.A pin 83 is positioned in openings 84 and 85 in the drive shaft 59 andextends through the slot 81a in the shaft 81.

A generally cylindrical cup or sleeve 86 having an inside diameterslightly greater than the diameter of the drive shaft is received on thedrive shaft and retained thereon by the radially reduced end portions83a of the pin. The pin ends 83a extend through openings 87 (FIG. 9) inthe cup, which are slightly larger than the diameter of the centralportion of the pin.

The shaft 81 carries a ring 88 which may be swaged onto the shaft orwhich may be a snap ring or the like received in a suitable annulargroove in the shaft. A helical spring 89 is positioned on the shaft 81between the ring 88 and the bottom wall 86a of the cup and urges the cupdownwardly with respect to the shaft 81 so that the upper portion of theperiphery of the openings 87 press against the pin ends 83a. The cup issecured against further axial movement away from the drive shaft, andthe pin 83 is prevented from inadvertent displacement from the driveshaft by the cup since the enlarged central portion of the pin cannotpass through the cup openings 87 unless the cup is lifted against thebias of the spring.

The shaft 81 extends axially through the central bore 65 of thedistribution head, and the upper end of the bore is closed by ametal-to-metal face type seal provided by a stationary bronze bushing 90and a rotating hardened steel ring 91. The bushing 90 is provided with acentral opening for rotatably receiving the shaft 81 and is seen toinclude an annular shoulder 90a which provides a flat lower surfacewhich extends radially outwardly beyond the wall of the bore 65. Theshoulder 90a is received in an annular recess 61a in the mounting block61 and held firmly against the distribution head 63. An O-ring 92 isreceived by a suitable annular recess in the bushing and provides a sealbetween the bushing and the distribution head.

Tl-le lower end of the bushing is provided with an inclined conicalbearing surface 90b which mates with a corresponding shaped bearingsurface 91a on the steel ring 91. The shape of the bearing surfaces mayalso be spherical or the shape of some other surface of revolution.

The lapped hardened steel ring 91 is secured to the shaft 81, as byepoxy adhesive or the like, and the steel ring is anchored againstdownward movement by a ring 93 which is swaged or otherwise secured tothe shaft 81. Suitable abutment or shoulder means other than the ring 93may also be used. The bearing surface 91a of the steel ring 91 is urgedfirmly against the bearing surface 90b of the bushing by the spring 89which urges the shaft upwardly with respect to the cup 86 and the driveshaft 59. The spring 89 also insures that the slotted end 82 of theshaft does not fall below the pin 83.

The mixing vane 80 extends substantially the full length of the chamberprovided in the mixing housing and may advantageously be formed from anelongated flat strip of aluminum which is twisted into a helix andprovided with a plurality of notches 920 which are spaced alternatelyalong the opposite longitudinal sides thereof.

Referring to FIG. 4, the flat upper end of the mixing vane is slidablyreceived by a slot 94 provided in the lower end of the driving shaft 81,and the mixing vane is free to float transversely and seek its owncenter within the mixing chamber, thereby eliminating the need for closetolerances within the mixer housing. The mixing vvane may also slidesomewhat axially within the chamber.

Resin A is delivered to the distribution head 63 through inlet port 66and enters the distribution chamber 65 through the inlet port 68.Similarly, resin B which is pumped by pumped 11 through conduit 14enters the distribution chamber through inlet port 67 and passage 69. Itwill be seen that the two resins enter the distribution chamber ataxially spaced locations and that resin A will predominate in the upperend of the chamber around the seal provided by the steel ring 91 andbushing so that the proper proportions for a hard mix are not present inthis area. Accordingly, if any of the material should leak through theseal it would not adhere to the members and prevent proper action.

The resin materials flow downwardly into the mixing chamber 71 wherethey are mixed by the rotating vane 80 and forced axially downwardlythrough the nozzle 15. The alternating notches of the vane allow resinmaterial to adhere to the wall of the mixer housing 70 for a discreteperiod of time before being swept off by the diametrically oppositeportion of the vane, thereby preventing the resin from being whirledabout as a unit within the mixing chamber and assuring good mixing. Thehelical shape of the mixing vane not only allows the vane to find itsown center within the mixing chamber but contributes to axial motion ofthe resin materials so that blending is obtained both axially andcircumferentially within the mixing chamber. Further, the free-floatinghelical vane can wipe resin material from the walls of the mixer housingso that there is no buildup of cured resin during operation.

The free-floating feature of the helical vane is of considerableimportance if for any reason a material is allowed to harden in thechamber. The mixer must then be disassembled, and with the usual designwhere a complicated multi-bladed agitator is fixed firmly to the shaft,it is very difficult to disassemble the mixer or to remove the bladesfrom the solidified resin. My mixer, however, can be readilydisassembled merely by removing the bolts 76. The mixer housing andhelical vane can thereafter easily be pulled away from the driving shaft81 since the vane is slidably retained therein. The mixing housing isadvantageously made of stainless steel and the vane made of aluminum sothat in the event of very solidly cured resin within the mixer housing,it is possible to drill out the accumulation of resin and the aluminumagitator. The agitator is relatively simple and can be readily andeconomically replaced.

If resin material does leak through the seal between the distributionhead 63 and the mounting block 61, openings 95 in the central portion ofthe mounting block permit the resin material to flow outwardly, therebypreventing resin from reaching the motor and interfering with itsoperation.

The conduits l3 and 14 which connect the mixer to the measuring pumpsare. preferably provided by flexible tubing to permit the mixer to bemoved relative to the pumps. The ejector nozzle of the mixer may therebybe guided by the operator to apply material in different locations.

The mixer can be readily disassembled for cleaning merely by removingthe bolts 64 and 76 to separate the motor section, distribution sectionand mixing section. If necessary, bolts 60 can be removed to permitseparation of the mounting block from the motor 58. The shaft 81 caneasily be detached from the drive shaft 59 by lifting the cup 86slightly upwardly against the bias of the spring so that the enlargedcentral portion of the pin 83 can be pushed through the openings 87 inthe cup. This step can be performed through the access openings 95 inthe mounting block.

However, after the mixer has been used and is to be shut down, it isvery easy to clean the mixer without disassembly. The flow of resinmaterial will stop by closing the valve that admits pressurized air tothe driving air cylinders of the pumps. Solvent may then be admitted tothe mixing chamber of the mixer, and, for this purpose, the distributionhead may be provided with an inlet port similar to inlet ports 66 and67. The solvent is pumped through the mixer while the vane is rotated,and a few ounces of solvent is usually enough to accomplish cleaningwithin a matter of minutes. Tl-le elongated, narrow mixer housing 70permits the mixer to be thoroughly cleaned with only a small amount ofsolvent. It is not necessary to clean the measuring pumps 10 or 11 ortheir delivery conduits 13 and 14, since these parts contain only asingle resin which will not harden until mixed with the other.

Referring now to FIGS. 1 and 2, the means for obtaining synchronismbetween the two measuring pumps 10 and 11 comprise simple hydrauliccircuits 98 and 99. The portion of cylinder 19 of pump 10 below thepiston assembly 26 is filled with suitable hydraulic fluid such ashydraulic oil or the like, and the portion of the cylinder above thepiston is filled with air. The port 22 of the cylinder is connected byconduit 100 to hydraulic fluid reservoir 101, and a micrometer needlevalve 102 is interposed in the conduit between the fluid reservoir andthe pump. Check valve 103 in bypass conduit 104 bypasses the micrometerneedle valve to permit fluid to flow from the fluid reservoir to thepump without restriction, but the flow of fluid from the pump to thefluid reservoir can be very accurately controlled by the micrometerneedle valve 102.

Resin material is pumped by pump 10 by admitting pressurized air fromair source 52 through valve 105 into cylinder 19 to move the piston rod24 and plunger 39 downwardly, and the speed of the downward movement ofthe plunger is accurately regulated by the setting of the micrometerneedle valve. The desired speed of operation can therefore be obtainedregardless of the viscosity of the resin that is being pumped.

Each of the measuring pumps has a similar hydraulic circuit, and themicrometer needle valve of each circuit can be set so that the cylindersof each pump operate in unison. Synchronism of the pumps preventsStratification of the resins in the mixing chamber which might occur ifone pump was delivering resin when another was not and also insures thatthe resins are always fed in the proper proportion even if only apartial stroke of the measuring pumps is utilized.

When the plunger of the measuring pump is to be returned, the valve 105directs pressurized air through conduit 106 to force fluid from fluidreservoir 101 through check valve 103 and into the cylinder 19 throughport 22 to return the piston assembly 26. As discussed hereinbefore, thereturn stroke of the piston rod can be very rapid, and fluid can flowinto the cylinder through the check valve in an unrestricted manner.

The oil in the cylinder 19 below the piston 26 lubricates the piston rodand prevents accumulation of resin around the packing gland of thepiston carried by block 23. Oil will not enter the resin portion of thesystem, since the pressure of the resin is considerably higher than thepressure on the oil.

The hydraulic circuits 98 and 99 insure simultaneous operation of aplurality of measuring pumps without any interconnection therebetween,and it is possible to have two, three, or more resin measuring pumpsoperating together. The hydraulic circuit synchronism means isespecially useful on pumps which are intended for small volume resinpumping. If the volume of resin materials which is to be pumped isrelatively large and large volume measuring pumps are used, the oilreservoirs of the hydraulic circuit synchronism means might be toolarge, and I have found that it is desirable to achieve synchronizationthrough a mechanical interconnection between the measuring pumps.

REferring to FIGS. and 11, measuring pump 110 supported by platform 111and stand 111a includes a cylinder 112 and plunger or piston 113. Themeasuring pump 110 is similar to the measuring portion 18 of the pump 10and is provided with a central bore 114 having a measuring chamber 115and radially enlarged outlet portion 116. Material to be pumped entersthrough inlet port 1 17 and flows into the enlarged inlet chamber 118provided by the intersection of the larger bore of the inlet 117 withthe smoother central bore 114. During the pumping stroke of the plunger,resin flows through central bore 119 of the plunger and through fourcross-drilled holes 120. However, a modified sealing means for theoutlet end of the pump is shown in FIGS. 1419 and 11. The cross drilledholes are provided through an annularly reduced portion 121 of theplunger, and a sealing O-ring 122 is received by an annular groove 123provided by a further annularly reduced portion of the plunger. TheO-ring is retained in the annular groove 123 between the radiallyenlarged annular portion 121 and the radially enlarged main portion ofthe plunger.

The particular cylinder 112 illustrated is formed of forward andrearward portions 112a and 112b, respectively, which are sealed togetherby O-ring 124. The bore 114 is provided with an annular enlargement 125in rearward portion 112b which receives a sealing ring 126 having agenerally U-shaped or cup-shaped cross section. The sealing ringprovides a seal between the plunger and the cylinder wall and preventsleakage of the resin.

As the plunger moves forwardly, or to the right in FIG. 10, resin flowthrough the cross drilled holes 120 into the annular space between thewall of the bore 114 and the annularly reduced plunger portion 121. Theresin will not flow into the enlarged outlet portion 116 of the boreuntil the O-ring 122 passes the inclined shoulder 127 which joins thebore 114 and the radially enlarged outlet portion 116. However, as soonas the O-ring passes the shoulder 127, resin flows into the outletportion 116 throughout a full 360 and the outlet end of the pump becomesfully open.

When the plunger is retracted, the outlet end of the pump remains fullyopen until the O-ring 122 engages the shoulder 127, at which time theoutletend will become fully closed. Thus, very little axial movement ofthe plunger is required to bring the outlet end from a fully closed to afully open position and vice versa.

Equivalent operation can be obtained by mounting the O-ring 122 in thewall of the cylinder and providing the shoulder on the plunger.

The inlet end of the pump is constructed similarly to that of the pump10 hereinbefore described. Because of the enlarged inlet chamber 118,full 360 inward flow of resin is obtained as soon as the plunger endpasses to the left of the inlet chamber wall 118a, and very little axialmovement of the plunger is required to obtain full flow.

The O-ring 122 is positioned relative to the shoulder 122 and theforward end of the plunger so that the O- ring will pass the shoulder topermit outflow at the same time or very shortly after the plunger endpasses the inlet chamber wall 1 18a to close off inflow.

Either sealing means for the outlet end of the pump may be used thatshown in FIGS. 2 and 3 or that shown in FIGS. 10 and 11. Each sealingmeans utilizes a resilient O-ring of rubber or other suitable materialwhich is not affected by the resin, and the O-ring provides desiredelasticity.

An elongated link 128 is pivotally connected at 129 to the rearward endof plunger 113, and the ink is connected to a rotatable cross-shaft 130by crank arm 131. The crank arm 131 is fixedly secured to thecross-shaft 130 and is provided with an adjusting slot 132 whichslidably and rotatably receives pin 133 which extends transversely fromthe elongated link 128. The pin 133 can be provided with a threadedouter end, and the pin can be secured in a desired position along thelength of slot 132 by means of nut 134. Cross-shaft 130 is journaled inbushings 135 mounted on platform 11] and is connected to a suitabledrive power source for imparting reciprocatory rotary motion to thecross-shaft, for example, a double acting air cylinder provided withcrank linkage for trAnslating linear reciprocatory motion into rotaryreciprocatory motion.

The other pumps of the mixing system are similarly provided withconnecting links and crank arms for mechanically connecting the plungersthereof to the cross-shaft 130, and the effective stroke of each of themeasuring pumps can be varied by sliding the connecting link 128 alongthe slot in the associated crank arm. It will be seen that when the link128 and plunger 113 are axially aligned, the slot 132 is inclined from aline x perpendicular to this common axis at an angle 0 of about 12. Thisslight angle will cause the connecting link 128 to move downwardly asthe pin 133 is moved from the outer end of the slot toward thecross-shaft 130, and the effective length of the crank arm 131 isreduced while the position of the lower end of the plunger of themeasuring pump is changed relative to the inlet port for the resinmaterial. As explained hereinbefore, the early part of the downwardstroke of the plunger is used in closing the material inlet port, and itis only after this port is closed by the plunger that pumping actionstarts. It is therefore necessary to slightly advance the lower end ofthe plunger as the total stroke is reduced in order that the proportionof the port-closing and pumping-portion of the stroke be kept constant.Changing the effective length of each crank arm will change the speed ofthe associated plunger but each plunger will start and stop pumping atsubstantially the same time because of this adjustment to the relativestarting positions of the plungers. It is important that each pump startand stop pumping at substantially the same time so that the proportionsof the various resins being delivered to the mixer remain constant.

The slidable engagement between the pin 133 and slotted crank arm andthe angle 0 are selected to retain the same ratio of inlet porting topumping stroke in order to afford simultaneity of delivery to the mixingchamber. In one specific embodiment the angle 0 was about 12, the centerof the shaft 130 was about 1-1 1/ 16 inches below the axis of theplunger, and the center of the pin 133 was about 1 inch to the left ofthe center of the shaft 130 when the link 128 was axially aligned withthe plunger.

The apparatus described herein is essentially of the shot-type, i.e.,the apparatus delivers a predetermined quantity of properly proportionedmixed material. This is particularly useful when it is desired to fillcontainers or cavities or to pot connectors with a predetermined amountof material. A further advantage is that the operator would readily notea change in the size of the shot that is delivered by the mixer andwould be made aware of some malfunction in the system such asinsufficient material in one of the reservoirs, a clogged line, or thelike. With continuous flow type machines, there is no indication of achange in the proportion of the components, and the machine mightcontinue to be used even though the material will not properly cure. Mysystem can be adjusted, however, to give one measured stroke afteranother to provide an essentially continuous flow. 1

If desired, the pumps may be provided with suitable means to protect theequipment in the event one of the plungers becomes jammed, for example,overload clutches, springs, shear pins, and the like.

While in the foregoing specification l have described specificembodiment of my invention in considerable detail for the purpose ofillustration, it is to be understood that many of the details hereingiven may be varied considerably by those skilled in the art withoutdeparting from the spirit and scope of my invention.

lclaim:

1. A mixing apparatus for mixing two or more materials comprising anelongated mixer housing providing a mixer chamber therein, said housinghaving an inlet and an outlet end and being provided with an inlet portadjacent the inlet end thereof for each material to be mixed, anelongated mixing vane rotatably received by the mixing chamber,rotatable drive shaft means, means for connecting the drive shaft meansto the mixing vane for rotating the vane whereby the materials enteringthe inlet ports are mixed and delivered to the outlet end of thehousing, seal means for closing the inlet end of the mixer housing, thedrive shaft means including an elongated shaft, the seal means includinga stationary portion rotatably receiving the elongated shaft and arotating portion secured for rotation with the elongated shaft, andspring means on the elongated shaft for urging the rotating seal portionagainst the stationary seal portion.

2. The apparatus of claim 1 in which the drive shaft means includes adriving shaft, connecting means between the driving shaft and theelongated shaft securing the elongated shaft for rotation with thedriving shaft but permitting relative axial movement between the shafts,the elongated shaft including abutment means thereon, a sleeve carriedby the driving shaft and secured against axial movement toward the sealmeans, said sleeve extending from the driving shaft toward the sealmeans beyond the abutment means on the elongated shaft and including aradially inwardly extending portion between the abutment means and theseal means, said spring means including a helical spring ensleeved onthe elongated shaft between the abutment means and the radially inwardlyextending portion of the sleeve whereby said abutment means is urgedaway from the inwardly extending sleeve portion.

3. The apparatus of claim 2 in which the driving shaft is provided witha bore which slidably receives one end of the elongated shaft, said oneend of the elongated shaft being slotted, the connecting means includinga pin extending transversely through the driving shaft and through theslotted end of the elongated shaft.

4. The apparatus of claim 3 in which said pin extends through openingsin the sleeve and restrains the sleeve against axial movement toward theseal means.

5. The apparatus of claim 1 in which the stationary portion of the sealmeans is provided with a bearing surface of revolution and the rotatingportion of the seal means is provided with a bearing surface ofrevolution matingly engaging the bearing surface of the stationaryportion.

6. A mixing apparatus for mixing two or more materials comprising anelongated mixer housing providing a mixer chamber therein, said housinghaving an inlet and an outlet end and being provided with an inlet portadjacent the inlet end thereof for each material to be mixed, andelongated mixing vane rotatably received by the mixing chamber, a driveshaft having a slotted end slidably receiving the mixing vane, the mixerhousing including a distribution portion provided with a central boreand an elongated mixing portion provided with acentral bore aligned withthe bore of the distribution portion, the inlet ports being provided inthe distribution portion and the distribution portion being boltablysecured to the mixing portion whereby the mixing portion can be removedfrom the distribution portion and the mixing vane can e removed from thedrive shaft.

7. The apparatus of claim 6 including a motor for rotating the driveshaft and a connecting portion for connecting the motor to thedistribution portion, the connecting portion being boltably secured tothe distribution portion.

8. A mixing apparatus for mixing two or more materials comprising anelongated mixer housing providing a mixer chamber therein, said housinghaving an inlet and an outlet end and being provided with an inlet portadjacent the inlet end thereof for each material to be mixed, anelongated mixing vane rotatably received by the mixing chamber, a driveshaft having a slotted end slidably receiving the mixing vane, a motorfor rotating the drive shaft, and a connecting portion boltably securedto the mixing housing for connecting the motor to the mixer housingwhereby the mixer housing can be removed from the connecting portion andthe mixing vane can be removed from the drive shaft 9. A mixingapparatus for mixing two or more materials comprising an elongated mixerhousing providing a mixer chamber therein, said housing having an inletand an outlet end and being provided with an inlet port adjacent theinlet end thereof for each material to be mixed, an elongated mixingvane rotatably received by the mixing chamber, rotatable drive shaftmeans, means for connecting the drive shaft means to the mixing vane forrotating the vane whereby the materials entering the inlet ports aremixed and delivered to the outlet end of the housing the mixer housingincluding a cylindrical distribution head provided with a central boreand an elongated generally cylindrical mixer portion provided with acentral bore axially aligned with the bore of the distribution head, oneend of the mixer portion being provided with a radially outwardlyextending shoulder, an annular clamping ring engaging said shoulder andbeing boltably secured to the distribution head, said inlet portscomprising generally radially inwardly extending passages provided in hedistribution head.

10. An apparatus for mixing a plurality of separate flowable materialsin desired proportions comprising a positive displacement piston pumpfor each material to be mixed, a mixer, conduit means connecting eachpump to the mixer for delivering the output of each pump to the mixer,means for regulating the piston displacement of each pump for deliveringthe materials to the mixer in the desired proportions, the mixer beingprovided with an elongated mixing chamber having an inlet end and anoutlet end, the inlet end of the chamber being provided with an inletport for each of the conduit means, a mixing vane rotatably received bysaid mixing chamber, power means for rotating the mixing vane to mix thematerials entering the inlet ports and to deliver the mixed material tothe outlet end of the mixer, each positive displacement piston pumpincluding a double-acting cylinder having a pair of axially spaced portsand a piston movable within the cylinder between the ports, the pistondisplacement regulating means including a liquid reservoir, meansconnecting the liquid reservoir to one of the cylinder ports fordelivering liquid to the cylinder, and valve means for permittingrelatively unrestricted flow of liquid from the liquid reservoir to thecylinder and for adjustably regulating the flow of liquid from the pumpto the liquid reservoir.

11. The apparatus of claim 10 in which the valve means includes a checkvalve interposed in the connecting means for permitting relativelyunrestricted flow of liquid from the liquid reservoir to the cylinderand a regulating valve interposed in the connecting means for permittingregulation of the flow of liquid from the cylinder to the liquidreservoir.

1. A mixing apparatus for mixing two or more materials comprising anelongated mixer housing providing a mixer chamber therein, said housinghaving an inlet and an outlet end and being provided with an inlet portadjacent the inlet end thereof for each material to be mixed, anelongated mixing vane rotatably received by the mixing chamber,rotatable drive shaft means, means for connecting the drive shaft meansto the mixing vane for rotating the vane whereby the materials enteringthe inlet ports are mixed and delivered to the outlet end of thehousing, seal means for closing the inlet end of the mixer housing, thedrive shaft means including an elongated shaft, the seal means includinga stationary portion rotatably receiving the elongated shaft and arotating portion secured for rotation with the elongated shaft, andspring means on the elongated shaft for urging the rotating seal portionagainst the stationary seal portion.
 2. The apparatus of claim 1 inwhich the drive shaft means includes a driving shaft, connecting meansbetween the driving shaft and the elongated shaft securing the elongatedshaft for rotation with the driving shaft but permitting relative axialmovement between the shafts, the elongated shaft including abutmentmeans thereon, a sleeve carried by the driving shaft and secured againstaxial movement tOward the seal means, said sleeve extending from thedriving shaft toward the seal means beyond the abutment means on theelongated shaft and including a radially inwardly extending portionbetween the abutment means and the seal means, said spring meansincluding a helical spring ensleeved on the elongated shaft between theabutment means and the radially inwardly extending portion of the sleevewhereby said abutment means is urged away from the inwardly extendingsleeve portion.
 3. The apparatus of claim 2 in which the driving shaftis provided with a bore which slidably receives one end of the elongatedshaft, said one end of the elongated shaft being slotted, the connectingmeans including a pin extending transversely through the driving shaftand through the slotted end of the elongated shaft.
 4. The apparatus ofclaim 3 in which said pin extends through openings in the sleeve andrestrains the sleeve against axial movement toward the seal means. 5.The apparatus of claim 1 in which the stationary portion of the sealmeans is provided with a bearing surface of revolution and the rotatingportion of the seal means is provided with a bearing surface ofrevolution matingly engaging the bearing surface of the stationaryportion.
 6. A mixing apparatus for mixing two or more materialscomprising an elongated mixer housing providing a mixer chamber therein,said housing having an inlet and an outlet end and being provided withan inlet port adjacent the inlet end thereof for each material to bemixed, and elongated mixing vane rotatably received by the mixingchamber, a drive shaft having a slotted end slidably receiving themixing vane, the mixer housing including a distribution portion providedwith a central bore and an elongated mixing portion provided with acentral bore aligned with the bore of the distribution portion, theinlet ports being provided in the distribution portion and thedistribution portion being boltably secured to the mixing portionwhereby the mixing portion can be removed from the distribution portionand the mixing vane can e removed from the drive shaft.
 7. The apparatusof claim 6 including a motor for rotating the drive shaft and aconnecting portion for connecting the motor to the distribution portion,the connecting portion being boltably secured to the distributionportion.
 8. A mixing apparatus for mixing two or more materialscomprising an elongated mixer housing providing a mixer chamber therein,said housing having an inlet and an outlet end and being provided withan inlet port adjacent the inlet end thereof for each material to bemixed, an elongated mixing vane rotatably received by the mixingchamber, a drive shaft having a slotted end slidably receiving themixing vane, a motor for rotating the drive shaft, and a connectingportion boltably secured to the mixing housing for connecting the motorto the mixer housing whereby the mixer housing can be removed from theconnecting portion and the mixing vane can be removed from the driveshaft
 9. A mixing apparatus for mixing two or more materials comprisingan elongated mixer housing providing a mixer chamber therein, saidhousing having an inlet and an outlet end and being provided with aninlet port adjacent the inlet end thereof for each material to be mixed,an elongated mixing vane rotatably received by the mixing chamber,rotatable drive shaft means, means for connecting the drive shaft meansto the mixing vane for rotating the vane whereby the materials enteringthe inlet ports are mixed and delivered to the outlet end of the housingthe mixer housing including a cylindrical distribution head providedwith a central bore and an elongated generally cylindrical mixer portionprovided with a central bore axially aligned with the bore of thedistribution head, one end of the mixer portion being provided with aradially outwardly extending shoulder, an annular clamping ring engagingsaid shoulder and being boltably secured to the distribution head, saidinlet ports coMprising generally radially inwardly extending passagesprovided in he distribution head.
 10. An apparatus for mixing aplurality of separate flowable materials in desired proportionscomprising a positive displacement piston pump for each material to bemixed, a mixer, conduit means connecting each pump to the mixer fordelivering the output of each pump to the mixer, means for regulatingthe piston displacement of each pump for delivering the materials to themixer in the desired proportions, the mixer being provided with anelongated mixing chamber having an inlet end and an outlet end, theinlet end of the chamber being provided with an inlet port for each ofthe conduit means, a mixing vane rotatably received by said mixingchamber, power means for rotating the mixing vane to mix the materialsentering the inlet ports and to deliver the mixed material to the outletend of the mixer, each positive displacement piston pump including adouble-acting cylinder having a pair of axially spaced ports and apiston movable within the cylinder between the ports, the pistondisplacement regulating means including a liquid reservoir, meansconnecting the liquid reservoir to one of the cylinder ports fordelivering liquid to the cylinder, and valve means for permittingrelatively unrestricted flow of liquid from the liquid reservoir to thecylinder and for adjustably regulating the flow of liquid from the pumpto the liquid reservoir.
 11. The apparatus of claim 10 in which thevalve means includes a check valve interposed in the connecting meansfor permitting relatively unrestricted flow of liquid from the liquidreservoir to the cylinder and a regulating valve interposed in theconnecting means for permitting regulation of the flow of liquid fromthe cylinder to the liquid reservoir.